The effect of modified atmosphere storage on the quality of fresh dill(Anethum graveolens L.) [poster]

Because of its high perishability, fresh dill (Anethum graveolens L.) cannot be stored for more than a few days, even at low temperature. The present study was therefore undertaken to determine whether modified atmospheres based on changes in CO2 and O2 concentrations would benefit dill storage. Dill cv. Ducat was cultivated between October 2009 and January 2010. Plants were harvested at the fresh market stage (before flowering) and randomly selected leaves were weighed, placed in airtight plastic bags and stored for 10 days at 5°C. The atmospheres within the containers (O2-CO2-N2) were initially as follows: (1) 20-0-80 (air), (2) 20-10-70, (3) 10-0-90, and (4): 10-10-80. The changes in O2-CO2 concentrations were monitored during storage; fresh weight, chlorophyll, vitamin C and total phenolics concentrations were measured before and after storage. The oxygen concentration within the bags during storage fell to 12.5% (treatment 1) and 17.9% (treatment 2) indicating a reduction of respiration due to the inclusion of 10% CO2 within the initial atmosphere (20% O2). At an initial concentration of 10% O2, the oxygen level decreased to 5.5% and 5.8% in the absence or presence of 10% CO2 (treatments 3 and 4), respectively. In each case, the decrease in O2 was accompanied by a corresponding increase in CO2 concentration. Weight loss during storage ranged from 2.6-5.3% and the total phenolics levels decreased in all treatments except treatment 3 (10-0-90). Vitamin C and chlorophyll concentrations decreased during storage. Vitamin C loss was similar in all treatments, but chlorophyll loss was significantly higher in the treatments with 10% CO2. In consequence, although modified atmospheres containing 10% CO2 reduce respiratory activity they are of questionable value for dill because the decrease in chlorophyll concentration causes a decrease in quality

The effect of controlled atmospheres on the composition and quality of dill (Anethum graveolens L. cv. Ducat) cultivated in spring and stored at two temperatures

This study was performed to evaluate four atmospheres varying in CO2 and N2 concentrations on the composition and quality of dill (Anethum graveolens L. cv. Ducat) during storage. Seeds were sown directly in the soil on 16/01/2010 and the plants harvested 93 days after sowing. The leaves (lamina and petiole) were weighed at harvest and immediately transferred to airtight plastic bags within which the atmospheres were modified by injection of O2, CO2 and N2. The treatments that were applied (O2-CO2-N2) were: (1): 20-0-80, (2): 20-5-75, (3): 20-10-70, (4): 20-15-65. All samples were stored for 14 days at 2 or 5°C and the gas composition within the bags maintained at the desired levels. From the results, it was found that weight loss during storage varied between 7 and 12% at 2oC and 13 and 17% at 5oC irrespective of the gas composition. Vitamin C concentration decreased during storage, but at both storage temperatures the decrease was less at the highest CO2 level. The concentration of total phenolics decreased during storage, irrespective of the composition of the storage atmosphere. There was a loss of chlorophyll during storage, which tended to be greater at 5oC than at 2oC, but was prevented at both temperatures by the highest CO2 concentration. In consequence, leaves stored under a gas composition of 20-15-65 (O2-CO2-N2) were greener at the end of storage. This, in conjunction with the relatively higher vitamin C concentration in this treatment, indicates that 15% CO2 was the most suitable storage atmosphere for quality retention in dill, while the preferred temperature was 2oC due to lower weight loss

The Yield and Composition of Dill Essential Oil in Relation to N Application, Season of Cultivation and Stage of Harvest

The effect of nitrogen (N) fertilization, season of cultivation and stage of harvest on the growth, foliar essential oil composition and yield of dill (Anethum graveolens L. cv. Ducat) was studied in two consecutive crops. Seeds were sown in October (autumn-winter crop) and January (spring crop) and the plants transplanted to a substrate of peat and perlite (1:1 v/v) 30 and 39 days later, respectively. Nitrogen (NH4NO3) was applied weekly at four levels (50, 150, 300, 450 ppm) in a completely randomized design. The plants were harvested at 158 (autumn-winter crop) and 83 (spring crop) days after sowing. The plant foliage was weighed and the essential oils were isolated by hydro-distillation and analyzed by GC/MS. The foliage fresh weight per plant progressively increased with increasing N up to 450 ppm in the autumn/winter, but was maximal at 300 ppm N in the spring. The essential oil concentration within the foliage was low and was unaffected by N application in the autumn/winter, but was significantly higher at 300 ppm N than at other N levels in the spring. The main components of the foliar essential oil were α-phellandrene, β-phellandrene, dill ether, α-pinene, β-pinene, α-thujene, myrcene, and π-cymene. In both crops α-phellandrene was the principal constituent. In the spring the concentration of all the essential oil constituents identified (except π- cymene) was highest at 300 ppm N, whereas in the autumn/winter crop the concentrations of α-phellandrene, β-phellandrene and dill ether were also higher at 300 ppm N, but the other constituents were not affected by higher N. It is concluded that for the autumn/winter crop 450 ppm N is optimal for biomass and foliar oil yield (biomass x oil concentration) whereas in the spring 300 ppm N is recommended

Osmoconditioning of lettuce seed to alleviate adverse effects of salinity on germination and early growth

Osmoconditioning of lettuce (Lactuca sativa L) seed improved tolerance to salinity, resulting in a higher rate and percentage of germination and increased plant height, fresh and dry weight at the stage of transplantation (6 weeks after sowing). The efficacy of osmoconditioning on plant growth varied with cultivar, being greater for cv. Cristel and Juventa and less for cv. White Boston. It is proposed that osmoconditioning offers a practical means of confronting problems of salinity in regions where lettuce is sown and irrigated with low quality water